“That came just hours after the UN convoy arrived,” he told reporters.

“Obviously such attacks are unacceptable in any circumstance but in this case they also hampered the delivery and distribution of badly needed assistance.”

Toner said the fact that Assad had allowed the convoy in to the town at all was “positive, but only a partial delivery and we would call for the rest of the supplies to be delivered as as soon as possible.”

And he said that only the United Nations should decide where and when to distribute aid inside Syria and that the fate of hungry populations must not be left to the regime.